Opensim Grader submission grader

[scarroll32]

I've seen a single instance of the error below. @spMohanty can you look into this?

Sep 19 10:14:25 crowdai-prd app[web] INFO 15 TID-1als9g INFO: Key starting with: d901 received, status: true
Sep 19 10:14:25 crowdai-prd app[web] INFO 15 TID-1als9g INFO: method=GET path=/api/opensim_gradings/API_KEY_REDACTED%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00 format=*/* controller=Api::OpensimGradingsController action=show status=500 error='ArgumentError: string contains null byte' duration=10.10 view=0.00 db=3.50 request_id=e81c7fb9-0d2b-4499-9e01-3582cb8219f4 user_id=#<NullParticipant:0x007f45e0b16bb0> params={"id"=>"API_KEY_REDACTED\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000"}
Sep 19 10:14:25 crowdai-prd app[web] FATAL 15 TID-1als9g FATAL:   
Sep 19 10:14:25 crowdai-prd app[web] FATAL 15 TID-1als9g FATAL: ArgumentError (string contains null byte):
Sep 19 10:14:25 crowdai-prd app[web] FATAL 15 TID-1als9g FATAL:   
Sep 19 10:14:25 crowdai-prd app[web] FATAL 15 TID-1als9g FATAL: app/controllers/api/opensim_gradings_controller.rb:7:in `show'
Sep 19 10:14:25 crowdai-prd heroku[router] info at=info method=GET path="/api/opensim_gradings/API_KEY_REDACTED%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00" host=www.crowdai.org request_id=e81c7fb9-0d2b-4499-9e01-3582cb8219f4 fwd="34.199.151.64" dyno=web.2 connect=1ms service=20ms status=500 bytes=1714 protocol=https

[scarroll32]

Will be handled in the #327 refactoring.

[scarroll32]

These keys will be rejected by crowdAI. Incorporated onto #327